1. Field of the Invention
The present invention relates to an embroidery machine for embroidering a predetermined pattern on fabrics and more particularly to an embroidery machine which includes a smoothing circuit for modifying the segmental displacement of the fabric to be embroidered in accordance with a scaler to smooth undesirable jagged edges of the predetermined pattern which may be accentuated upon a change in size of the predetermined pattern. The machine further includes an inhibit circuit for inhibiting the smoothing means upon the sensing of a predetermined condition and a centering control for moving the cloth frame relative to the sewing head around the periphery of the predetermined pattern to be embroidered subsequent to the fabric being manually centered under the needle with respect to the desired position of the predetermined pattern to be embroidered. A control is also provided to allow the machine to vary the space between distinct spaced apart portions of the pattern to be embroidered in two coordinate directions.
2. Background of the Invention
Automated embroidery machines are known in the art. An example of the known embroidery machines is disclosed in the Ramsey et al U.S. Pat. No. 3,385,244 and in the Scherr U.S. Pat. No. 3,448,705. Both of these patents disclose typical drive systems for driving the fabric of an embroidery machine relative to a sewing head in two coordinate directions, i.e., on X and Y axes.
In many cases it is desired to be able to vary the size of a particular pattern to be embroidered depending on the size of the goods on which the particular pattern is to be embroidered. Generally, the predetermined pattern to be embroidered is represented by signals in a signalling means which need to be modified in order to change the size of the predetermined pattern. In the known machines, the size of the pattern is generally multiplied or divided to scale the pattern. The Reeber, et al U.S. Pat. No. 3,208,414 shows a means for varying the size of the pattern which is a mechanical cam means. In systems such as Reeber's jagged edges of the design will be exaggerated and not smoothed out when the design is expanded. The Bihaly U.S. Pat. No. 3,079,880; the Yanikoski U.S. Pat. No. 3,970,016; and the Muller U.S. Pat. No. 3,938,543 all disclose different control systems for sewing machines, but none discloses means for smoothing the predetermined pattern to be embroidered when the pattern is expanded. Each predetermined pattern consists of a plurality of linear segments. When a pattern in the prior art machines was expanded, generally the individual segments were enlarged according to the desired size of the pattern to be embroidered. Since the prior art machines do not smooth expanded patterns, many times jagged edges of the design are accentuated upon enlargement of the design. An alternative method of scaling without using smoothing would be to store the pattern for the largest size design to be sewn and then divide the pattern to get smaller sizes of the design. While such an approach would not accentuate the jagged edges of the design, it would necessitate a pattern storage capability about 25 times larger than that contemplated with the present design. Of course, it would be possible to have a separate pattern stored for each desired size of the pattern, but this would require an even larger memory.
The present invention overcomes the problems of prior art by providing a smoothing circuit which smoothes jagged edges of the design when the design is expanded. An inhibit circuit is provided for inhibiting the smoothing circuit during certain conditions in which it is not desired to smooth the expanded pattern. Such cases occur when sharp edges of a predetermined pattern are desired such as on a monogram of a letter wherein the corners of the letter are supposed to be distinct.